This detailed study of the different rates of growth of parts of the body relative to the body as a whole represents Sir Julian Huxley's great contribution to analytical morphology, and it is still a basis for modern investigations in morphometrics and evolutionary biology. Huxley was the first to put the concept of relative growth - or allometry - upon a firm mathematical foundation, and since publication of this book in 1932, his work has been found to have greater implications than even he imagined. Problems of Relative Growth is at once a formulation of the basic principles of allometry and a survey of its many and various occurrences and applications. Examples are taken from such widely divergent areas as the development of the large claw in male fiddler-crabs, the size and number of points of deer antlers, heterogony in neuter social insects, the disproportionate growth of the human head from infancy to adulthood, and the formation of spiral shapes in certain mollusk shells and of the curved shape of the rhinoceros' horn. Starting from the fact of obvious disharmonic growth, Huxley formulates his first and fundamental law - that of the Constant Differential Growth Ratio. He then demonstrates that the distribution of growth potential occurs in an orderly and systematic way - that there are growth-gradients culminating in growth-centers. Other topics treated include multiplicative and accretionary kinds of growth, the role of hormones and mutations, and the relevance of the entire investigation to the problems of orthogenesis, recapitulation, vestigial organs, the existence of nonadaptive characters, physiological genetics, comparative physiology, and systematics. In theirintroduction to this unabridged facsimile republication of the original 1932 edition, Frederick B. Churchill and Richard E. Strauss place Huxley's work in the context of modern research in history and biology.

The evolutionist Ernst Mayr considered August Weismann "one of the great biologists of all time." Yet the man who formulated the germ plasm theory-that inheritance is transmitted solely through the nuclei of the egg and sperm cells-has not received an in-depth historical examination. August Weismann reintroduces readers to a towering figure in the life sciences. In this first full-length biography, Frederick Churchill situates Weismann in the swirling intellectual currents of his era and demonstrates how his work paved the way for the modern synthesis of genetics and evolution in the twentieth century. In 1859 Darwin's tantalizing new idea stirred up a great deal of activity and turmoil in the scientific world, to a large extent because the underlying biological mechanisms of evolution through natural selection had not yet been worked out. Weismann's achievement was to unite natural history, embryology, and cell biology under the capacious dome of evolutionary theory. In his major work on the germ plasm (1892), which established the material basis of heredity in the "germ cells," Weismann delivered a crushing blow to Lamarck's concept of the inheritance of acquired traits. In this deeply researched biography, Churchill explains the development of Weismann's pioneering work based on cytology and embryology and opens up an expanded history of biology from 1859 to 1914. August Weismann is sure to become the definitive account of an extraordinary life and career.